Corn’s nitrogen needs extend into season

WACO, Texas — Through genetic advancements, corn is utilizing more nitrogen later in the season.

Researchers have found the corn plant consumes 55% of its total nitrogen demand from V6 to VT, and 40% from R1 to R6, according to Pioneer.

“We know from extensive research that corn uses a lot more nitrogen later in the season than it has in the past,” said Ron Joiner, Pioneer territory manager.

“In the last 10 years or so, corn is utilizing way more nitrogen post-tassel than it did in the years past, and that’s one of the reasons it’s a good idea to think about split applications of nitrogen.”

While sidedress applications of nitrogen are now a common practice, one of the frequent questions Joiner hears is if the cosmetic burn from urea on the leaves hurts the crop to the point where yield is impacted.

“A lot of times you’ll see that concentration of nitrogen or the pellets that go down in the whirl and cause some leaf burn, some cosmetic burn,” he said.

“The fact that the leaf is a solar panel for the corn plant, naturally you want to avoid anything like this if at all possible, but you also have to consider what the benefits are.

“I love to sidedress corn, and a situation where we do see some cosmetic leaf burn, we have to ask ourselves what’s the benefit of the additional nitrogen versus the cosmetic burn on the crop.”

Joiner compared it to the impact of herbicide applications.

“A lot of times your plants have to metabolize a herbicide, maybe show a flashing effect, maybe we stunt the plants a little bit, but the alternative is if you left the leaves and grass you wouldn’t have any yield,” Joiner noted.

“The same thing kind of goes along with this situation. You’re adding additional units of N at a proper time because if you’re going to be utilizing nitrogen post-tassel, you want to have a nitrogen source that’s readily available on out as far as you can for the best utilization of pounds of N per bushel.

“What I would tell you is in most instances, a little bit of cosmetic leaf burn compared to the overall benefit of split-applied nitrogen with urea is definitely worth the cost of the cosmetic burn on the leaves.”

However, Joiner added, every situation is different.

“So, be wise about how you do it. A few things you can do to minimize that burn — a lot of times if you add a coated urea, it’s a little bit less,” he said.

“If you can wait on those applications until the dew has dried in the morning, a lot of times those prills or pellets won’t stick to the leaves or won’t stay on there as long and don’t cause as much cosmetic burn.”